Michael Schumacher, now in his 44th year, produced the fastest time in testing in Jerez on Wednesday and cut a belligerent figure afterwards when he said: "I am still around to fight for the championship. Absolutely. Whether we can do it or not is something that will be proven this year."

The seven-times world champion is in the third and surely final year of his deal with Mercedes after an anti-climatic comeback. At the end of the season he is expected to leave the sport he dominated so ruthlessly while at Ferrari.

But he is not the only one under pressure. Last season was a desperately disappointing one for Mercedes, who finished fourth in the constructors' championship, 210 points behind the third-placed Ferrari, who themselves underperformed woefully.

Schumacher did improve his performances towards the end of the season but still finished eighth in the championship, one place behind team-mate Nico Rosberg, whose best position was fifth after making three podium appearances the previous year.

Mercedes are the only leading team at Jerez running with last year's car. They are due to launch their 2012 model at the next testing session in Barcelona on 21 February. There are rumours that the delay has been caused by their reluctance to reveal their new front wing.

A cautious Schumacher said: "I don't think we can realistically achieve a championship‑winning car immediately from where we started last year. We have to build our way there and I am confident we can do that in the future but let's take it step by step."

The German, who drove for Force India alongside Britain's Paul di Resta last season, was given an 18-month suspended sentence and also fined €200,000 following an incident in a Shanghai nightclub after the Chinese Grand Prix.